Originally designed by Carl Swebilius of High Standard, the M42 was intended as a competitor for the Thompson SMG in police and military contract sales. One of the last generation of "heavy metal" SMGs, the M42 used machined steel and polished wood much like the Thompson, though with a more streamlined design with easier takedown. Unable to commit to the design due to a massive U.S. order for M2 machine guns, High Standard sold the design to the United Defense Supply Corporation, a private outfit established and run by then-members of the British Purchasing Commission, who went to Marlin for the actual act of manufacturing. While the M42 achieved substitute standard status with the U.S. Army, it's main claim to fame is use with the Office of Strategic Services (who found the M42 to be more sensitive to dirt than the Thompson, but easier to clean and more accurate) and in airdrops in hostile territory. Traveling abroad, the M42 armed the partisans in Crete, Italy, Belgium, Denmark, Norway and France (with some unfortunately falling into the hands of the Free French's collaborationist nemesis, the Milice), as well as both the Nationalist and Communist Chinese forces facing off against Japan. Fitted with a fixed blade front and windage/elevation adjustable rear sights, with a circled "P" stamped on the right side of the chamber, the three-line address and model markings on the left side of the lower receiver, and the three-position selector ("SEMI-AUTO", "-SAFE-" and "AUTO") on the right side. The upper receiver is unnumbered, with the lower numbered "14522" (the serial number of record) and "14632". Other known examples have numbers in the same location on the lower receiver, typically in the 12xxx-15xxx range. Contoured front pistol grip and smooth buttstock, with a checkered steel trapdoor buttplate. Includes one standard magazine and one double magazine.

Very fine with 85% plus original blue finish, showing a number of light scratches, edge wear, and mild oxidization. A small area on the lower right side of the upper receiver near the magazine well has been ground/polished down and then touched up. The wood is fine, with mild dings and scratches. Mechanically excellent. NOTE: This weapon is a National Firearms Act (NFA), fully transferable Class 3, which is registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives, (BATFE) that is classified as a "Curios or Relic" as defined in 27 CFR, 478.11. These weapons are still subject to the provisions of 18 U.S.C. Chapter 44 and 27 CFR part 478.